In the prior art, a drill chuck generally comprises a chuck body, jaws, a nut, a front sleeve and a rear sleeve. For example, as set forth in Chinese Utility Model Patent No. 2322725 published on Jun. 9, 1999 a drill chuck is disclosed. Three jaws for the chuck are provided in three inclined bores distributed uniformly on the chuck body, respectively. Between the nut and the jaw, a thread connection is adopted. Moreover, a thrust bearing is provided in the rear end of the nut with a retaining ring being provided in the rear end of thrust bearing. The rear sleeve is mounted on the rear end of the drill body. The nut includes a duplex-half structure which is combined into an integral construction with a nut sleeve shrinking fit with the nut. Key connections are adopted for torque transmission between the front sleeve and the rear sleeve. Annular protrusions are defined on the inner surface of the front end of the front sleeve with annular recesses being provided to correspond with said protrusions in the drill body. Axial positioning of the front sleeve is carried out by engagement of the protrusions with the recesses. However, the disadvantages of the drill chuck lie in the key connections being adopted for torque transmission between the front sleeve and the nut sleeve. The, use of a single-side key would make the torque transmission off-balance. Furthermore, since axial positioning of the sleeve is carried out by the engagement between the annular protrusions defined in the inner surface of the front end of the front sleeve and said recesses defined in the drill body, the front sleeve is not easy to assemble, and the rear end has no engaging space so that the front sleeve and its rear end would result in a large vibration when being operated.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.